*4.5. Dip Coating Procedure*

There were 48 fish divided into four groups (each 12 fish). The mackerel fillet samples were skinned and washed with sterile water. Then the fillets were cut into portions of approximately 3.5 cm × 2.5 cm × 1.6 cm (10–15 g). The mackerel fillet samples were divided into 4 groups. The first group was soaked in sterile distilled water to prepare the control samples (uncoated). The other three groups were soaked in the XAN/EEP composite coating solution for 2 min to prepare the three coated treatments (XAN-EEP 0%, XAN-EEP 1%, and XAN-EEP 2%). The mackerel fillet samples were dipped in respective coating solutions (XAN-EEP 0%, XAN-EEP 1%, and XAN-EEP 2%) in a ratio of 1:2 (*w*/*v*) for 5 min and were then air dried on filter paper for 15–20 min. After that, each sample for each treatment was placed individually in a sterile zip plastic stomach bag under aerobic conditions and all packages were stored in the refrigerator at a temperature of 2 ◦C. Physical, chemical, microbial, and sensory analyses were carried out every 5 days, starting from 0 to over 20 days from the storage process.
